Facebook (4:19-cv-04355) has become the fifth defendant sued in the new litigation campaign of Utah plaintiff TransactionSecure, L.L.C., which hit DeviantArt, Fitbit, Microsoft (GitHub), and Stripe earlier in July. The defendants are accused of infringement through the use of the OAuth 2.0 protocol, a user authentication framework, on their respective websites, in this new case focusing on its use by Instagram. The asserted patent broadly concerns authenticating a user’s identity using a “trusted entity” with a repository that holds the user’s personal information.